Helena Christensen gets her kit off for Reebok

You'd think at 41, supermodel Helena Christensen would have started to feel envious of younger models starting out in the fashion industry - they're all tight bums, svelte thighs, toned tummys after all...

But she's not envious, and quite frankly we can see why. The Danish supermodel gets naked in a new advert for Reebok and she looks incredible. If anything her killer body is better than it was at 21. She might not be envious but we certainly are!

Of course, behind every amazing bod is a beauty secret. Helena's is Reebok's EasyTone trainers, designed to tone up the body.

The model explains: "I live in New York and I like to walk all over the city so having a pair of trainers that tone your legs and bum while walking is fantastic. They really feel like they work and I felt a difference in just a few weeks."